Regd VTK File Format and Paraview

Submitted by Somnath on Mon, 04/26/2010 - 02:41

Hi,

I am using the following dump command:
dump 480 all custom 10000 dump.pour id type x y z radius

However, when I convert it into vtk format using the vtk.py tool in pizza.py, the radius column in the dump file, I guess, is not getting written. Basically, I wish to visualise my simulations using Paraview, and I want the particles to be sized according to their radius using the glyph tool. Right now, atom_type is the only scalar that is being stored, so the particles are getting sized according to their id and not their radius.

Any help will be appreciated.

Thanks!
Som

-
Somnath Mondal
Graduate Research Assistant
Dept. of Petroleum and Geosystems Engineering
University of Texas at Austin

Forums:

ckloss's picture

ckloss | Mon, 04/26/2010 - 06:45

Hi Som,

please use the pizza.py version provided at cfdem.com. It comes with a short doc how to use it.
This patched version provides a routine called manyGran(), that can be used instead of the many() routine to write the VTK files. This manyGran() also writes radius, velocity, angular velocity and particle forces by default. It needs to be used with dump custom. In the LIGGGHTS examples, this dump custom command is used.

Regards,
Christoph

Somnath | Mon, 04/26/2010 - 18:12

Dr. Kloss,

Thank you for your prompt reply. I was using the pizza.py provided at cfdem.com (gran_pizza-16Mar09.tar.gz). However, I was still following the old documentation.

Regards,
Som

Somnath | Tue, 04/27/2010 - 21:08

Hi Som,

please refer to the LIGGGHTS examples that come with LIGGGHTS. They all contain valid commands for output with the updated pizza.py version.

Regarding question2: Sometimes, pizza.py "unscales" the dump although it should not, so the dump has to be scaled again afterwards.

Regards,
Christoph

thwagner | Wed, 07/07/2010 - 15:25

Hi Christoph,

I followed your instructions to use pizza.py for post-processing the LIGGGHTS examples, i.e. the cohesion example:

d = dump("post/dump.cohesion")
v = vtk(d)
v.manyGran("post/dump.particles.")

After executing the script the post directory is filled with two vtk files for every dump step:

dump.particles.0000_boundingBox.vtk
dump.particles.0000.vtk

Loading these VTK files into paraview I was able to color the particles by any scalar like v, omega, F, radius.

My question is how to glyph the particles as spheres with diameters according to its radius values?

I was not successful using the glyph filter ...

With kind regards,
Thomas Wagner.

ckloss's picture

ckloss | Wed, 07/07/2010 - 15:56

Hi Thomas,

the following steps should do it:

+make a glyph
+choose glyph type "sphere"
+choose radius = 1
+choose scale mode = scalar
+choose set scale factor = 1
+choose scalars = radius (at the top of "properties")
+press apply

best regards,
Christoph

rqwang | Fri, 03/11/2011 - 04:36

Hi Christoph,

Your instruction is working very well.

But I want to color the particles by its magnitude of velocity. In the "color by" of paraview, I cannot find anything related to velocity. Could you help me?

Thanks.

Ruo

Yansan | Sat, 03/12/2011 - 02:05

Chose in the glyph properties tab:
- vectors -> v

Then chose in the glyph display tab:
- color by -> GlyphVector

Maybe you have to rescale the color map.
Yansan